In a digital camera system, pixel signals obtained by an image sensor are converted into image data which is digital data. The image data is temporarily stored in a memory, and then image processing is performed thereon.
As the resolution of a digital camera system is enhanced and the number of pixels of an image sensor mounted in the digital camera system is increased, the amount of image data increases correspondingly, and thus the memory capacity required for temporarily storing image data also increases. In addition, since a large amount of image data is read and written, a large bandwidth needs to be secured for memory access. However, increasing memory capacity and bandwidth leads to rise in power consumption and cost.
Examples of a conventional technique for reducing memory capacity include an image processing apparatus disclosed in Patent Literature 1. The configuration of an image processing apparatus 1400 disclosed in Patent Literature 1 is shown in (a) of FIG. 12. An image pickup device 1413 performs image pickup, an A/D converter 1414 digitally converts pixel signals accumulated in the image pickup device 1413, and then an amplification means 1415 amplifies the digitally-converted pixel signals to generate digital image data. As shown in FIG. 13, the digital image data is divided into a plurality of rectangular blocks each having a predetermined size. Digital image data of each rectangular block is compression-encoded with a fixed amount of code, and is stored in a memory 1416. By compressing the amount of data in this manner, reduction in memory capacity is achieved.